Vancouver, British Columbia--(Newsfile Corp. - May 23, 2024) - Sienna Resources Inc. (TSXV: SIE) (OTC Pink: SNNAF) (FSE: A1XCQ0) ("Sienna" or the "Company") wishes to announce the acquisition of the new "Case Lake West Cesium and Spodumene Pegmatite Project" in the Larder Lake Mining division of Ontario, Canada, roughly 100 km north of Kirkland Lake, NE Ontario. This project consists of approximately 2,200 contiguous acres prospective for Cesium and Spodumene Pegmatites directly bordering Power Metals Corp's (PWM) Case Lake cesium and pegmatite swarm discovery. On May 22, 2024 Power Metals announced "WORLD-CLASS CESIUM RESULTS UP TO 18.13% AT CASE LAKE." This was very exciting news regarding this growing cesium district. Sienna management cautions that past results or discoveries on properties in proximity to Sienna may not necessarily be indicative of the presence of mineralization on the company's properties.

Case Lake West Cesium and Spodumene Pegmatite Project

Jason Gigliotti, President of Sienna states, "Management is pleased to be able to acquire the Case Lake West Cesium and Spodumene Pegmatite Project directly bordering Power Metal's Case Lake discovery. This area is very active currently and Management is looking to start operations as soon as possible. With the significant announcement by Power Metals on May 22, 2024 of their 'World-class cesium results...' Sienna's management is encouraged by these important results achieved directly bordering our property. Ontario is one of the most well-known mining regions in the world, and we are very pleased to have a large footprint in the heart of it. Management is very optimistic about the remainder of the year and how the overall tenor of the junior market is improving. Sienna has been building a strong portfolio of Canada focused assets in 2024 primarily in Uranium and now for Cesium and Lithium. Sienna management plans to continue and build on this trend in the future."

About Sienna Resources Inc.

Sienna has recently acquired the "Case Lake West Cesium and Spodumene Pegmatite Project" in Larder Lake Mining division of Ontario, Canada roughly 100 km north of Kirkland Lake, NE Ontario. This project consists of approximately 2,200 contiguous acres prospective for Cesium and Spodumene Pegmatites. Sienna has also just acquired the 10,357 acre "Uranium Town Project" bordering Denison Mines Corporation (DML, DNN) , the 10,845 contiguous acre "Dragon Uranium Project" bordering Cameco Corporation (CCO, CCJ) and the 55,440 acre "Atomic Uranium Project" in the world renowned Athabasca Basin of Saskatchewan. Also, Sienna recently expanded the "Elko Lithium Project" in Elko County, Nevada. This project consists of approximately 1840 contiguous acres directly bordering Surge Battery Metals' (NILI) "Nevada North Lithium Project" in Elko County, Nevada who announced the highest grade lithium deposit in the USA. Sienna is also one of the larger landholders in Clayton Valley Nevada. Sienna's Clayton Valley projects include the Blue Clay Lithium Project, the Silver Peak South Project, and the Clayton Valley Deep Basin Lithium Project. Clayton Valley is home to the only lithium production in North America, being Albemarle Corp's (NYSE: ALB) Silver Peak deposit. This project is also near Tesla Motors Inc.'s (Nasdaq: TSLA) Gigafactory in Nevada. On March 18, 2021, Schlumberger New Energy Venture (NYSE: SLB) announced the development of a lithium extraction pilot plant through its new venture, NeoLith Energy in a strategic partnership with Pure Energy (TSX.v: PE). The deployment of the pilot plant will be in Clayton Valley, Nevada, USA. The NeoLith Energy sustainable approach uses a differentiated direct lithium extraction (DLE) process to enable the production of high-purity, battery-grade lithium material while reducing the production time from over a year to weeks. Results from this pilot plant are expected in 2024 and could have a significant impact on the brine prospects within Clayton Valley Nevada as Sienna is located in the deepest section of this brine deposit.

This project was acquired via staking.

Qualified Person:
Mr. Frank Bain, PGeo, a qualified person as defined by National Instrument 43-101 has reviewed and approved the scientific and technical disclosure contained within this news release.

If you would like to be added to Sienna's email list, please email info@siennaresources.com for information or join our twitter account at @SiennaResources.

Contact Information
Tel: 1.604.646.6900
Fax: 1.604.689.1733
info@siennaresources.com

"Jason Gigliotti"
President, Director
Sienna Resources Inc.

Statements in this news release that are not historical facts are forward-looking statements. Forward-looking statements are statements that are not historical, and consist primarily of projections - statements regarding future plans, expectations and developments. Words such as "expects", "intends", "plans", "may", "could", "potential", "should", "anticipates", "likely", "believes" and words of similar import tend to identify forward-looking statements. Forward-looking statements in this news release include uncertainty of exploration and development plans regarding the property; commodity price fluctuations; political or economic instability and regulatory changes; currency fluctuations, the state of the capital markets; uncertainty in the measurement of mineral reserves and resource estimates; the Company's ability to attract and retain qualified personnel and management; potential labour unrest; reclamation and closure requirements for mineral properties and the availability of capital to fund the Company's projects, as well as other risks and uncertainties identified under the heading "Risk Factors" in the Company's continuous disclosure documents filed on SEDAR. You are cautioned that the foregoing list is not exhaustive of all factors and assumptions which may have been used. The Company cannot assure you that actual events, performance or results will be consistent with these forward-looking statements, and management's assumptions may prove to be incorrect. These forward-looking statements reflect current expectations regarding future events and operating performance and speak only as of the date hereof and the Company does not assume any obligation to update forward-looking statements if circumstances or management's beliefs, expectations or opinions should change other than as required by applicable law. For the reasons set forth above, you should not place undue reliance on forward-looking statements.

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